The mechanisms responsible for glycoprotein synthesis and secretion by the various mucus-secreting cell types (mucous and serous cells in the submucosal glands and goblet cells in the airway epithelium) in human bronchial mucosa are being analysed in vitro. The role of microtubules and microfilaments in the secretory process will be further elucidated, by electron microscopic and metabolic studies, and compared in the three cell types. Analysis of the effects of anti-inflammatory agents on glycoprotein synthesis and discharge will be extended to include other agents particularly indomethacin and phenylbutazone. The effects of these agents will be compared in normal and bronchitic airways. In addition, we will carry out a preliminary study of the effects of some inflammatory mediators, particularly histamine, prostaglandins and bradykinin. Detailed structural analysis of mucus glycoproteins secreted by explants of bronchial mucosa maintained for several days in organ culture will be carried out, i.e., molecular weight determination and analysis of amino acid and carbohydrate composition.